Cisco 400-007 Exam With Confidence Using Practice Dumps

B (Northbound APIs):Northbound APIs allow applications to communicate with the SDN controller to express service requests and provide policy intent. The controller translates these into instructions for the underlying infrastructure.

Other options explained:

A: Southbound APIs connect controllers to forwarding devices.

C: Orchestration coordinates workflows across domains but doesn’t directly connect applications to controllers.

D: The SDN controller receives the northbound API calls but is not the API itself.

D (Queue thresholding on the host subinterface):Protects CPU resources by limiting the amount of control plane traffic destined to the router itself.

E (Port filtering on the host subinterface):Allows fine-grained filtering of control plane traffic based on specific protocols or ports, protecting sensitive processes like routing protocols or management access.

Other options explained:

A, B, C: Transit subinterfaces protect forwarding plane transit traffic, not traffic destined to the control plane.

C (Layer 2 switches unaffected):IPv6 operates at Layer 3, so pure Layer 2 switches forward frames without needing IPv6 awareness. As long as switches can transparently forward Ethernet frames, IPv6 functionality will be preserved, minimizing unnecessary hardware upgrades.

Other options explained:

A/B/D: These unnecessarily increase cost and complexity for basic Layer 2 functionality where IPv6 awareness is not mandatory.